International Journal of Bioassays 6.6 (2017) pp. 5394-5398 *Corresponding Author: Dr. Avinash B. Taksande, Assistant Professor, Department of Physiology, JNMC, Sawangi (M), Wardha, Maharashtra State, India. E-mail: drabtaksande@gmail.com DOI: http://dx.doi.org/10.21746/ijbio.2017.06.003 pg. 5394 Case Study Comparative evaluation of Optical Coherence Tomography (OCT) with Pattern Reversal Visual Evoked Potential (PRVEP) in early primary open angle glaucoma Taksande Avinash*, Alka Rawekar 1 , P. G. Sune 2 1 Department of Physiology, JNMC, DMIMS(DU), Sawangi (M), Wardha, Maharashtra State, India. 2 Department of Ophthalmology, JNMC, DMIMS(DU), Sawangi (M), Wardha, Maharashtra State, India. Received: April 13, 2017; Accepted: May 20, 2017 Available online: 1 st June 2017 Abstract: Present study is to correlate the average retinal nerve fiber layer (RNFL) thickness and the visual function evaluated by electrophysiologic retinal and cortical responses assessed in primary open-angle glaucoma (POAG) eyes by a Case-control study. One hundred and sixty-one control and glaucoma patients (mean age, 55.18±5.19 years for study group and 54.45±4.81 years for control group) were selected in the study. Average Retinal Nerve fiber layer thickness was measured by optical coherence tomography. Retinal and visual pathway function was assessed by simultaneously recording pattern reversal visual evoked potentials (PRVEPs) Linear regression analyses were adopted to establish the correlation between average RNFL thickness and PRVEP parameters. Average Retinal Nerve fiber layer thickness were taken. PRVEP, P100 latency and N75-P100 amplitude were also measured. In POAG eyes, we found a significant (P< 0.01) reduction in average RNFL thickness with respect to the values observed in control eyes. PRVEP parameters showed a significant (p< 0.01) delay in p100 latency and reduced N75 p100 amplitude. Positive correlations between average RNFL values and PRVEP parameters were found. There is a positive correlation between PRVEP changes and average RNFL thickness, in POAG patients. Key words: Pattern Reversal Visual Evoked Potential; Optical Coherence Tomography; Primary Open Angle Glaucoma Introduction Glaucoma is fast emerging as a major cause of blindness in India second only to cataract [1] . Primary open-angle glaucoma is described distinctly as a multifactorial optic neuropathy that is chronic and progressive with a characteristic acquired loss of optic nerve fibers. Such loss develops in the presence of characteristic subjective visual field abnormalities and manifests by cupping and atrophy of the optic disc [2] . The damage results either from the direct mechanical effects of high intra – ocular pressure (IOP), from compromises to the vascular supply or from a combination of these and other factors. (3) Anatomical studies have documented that visual field defects usually develop only after the loss of 30% - 50% of ganglion cells. (4) Optical coherence tomography (OCT) is a noninvasive technique that allows cross – sectional imaging of the retina and quantifies the thickness of the retinal nerve fiber layer (RNFL) around the optic nerve head. The degree of RNFL thickness reduction has been shown to correlate with visual field defects (5) . OCT has been used successfully to capture retinal ganglion cell axon loss in early glaucoma and in other forms of anterior visual pathway disease, including traumatic optic neuropathy, chiasmal lesion, and acute optic neuritis. (6) Recording the spontaneous electrical activity of the brain from electrodes placed on the scalp has been a clinical practice for many years now. The visual evoked potential (VEP) is one of several evoked potentials that can be recorded from scalp electrodes. It is well acknowledged that VEPs are useful for investigating the physiology and pathophysiology of the human visual system, including the visual pathways and visual cortex [7] . The pattern visual evoked potential (VEP) has been shown to be sensitive to optic nerve lesions caused by demyelinization, ischemia, and compression of the anterior visual pathway. Glaucoma has also been reported to affect the VEP by causing both reductions in amplitude and increases in latency. Increased pattern VEP latency has been associated with optic disc cupping and the presence of visual field loss [8] . Electrophysiological methods may also be used to identify early structural and functional damage in